The primary objective of the proposed research is to develop a resource for the study of genetic and environmental factors in behavioral aging. The Swedish and Finnish twin registers will be searched to ascertain a sample of elderly identical and fraternal twins reared apart. A battery of measures relevant to behavioral aging will be developed for subsequent studies utlizing this unique sample. We propose to construct a coherent battery of reliable, efficient, and valid measures that are factorially representative of the following domains: specific cognitive abilities, information processing, psychomotor skills, and personality. The battery will also include questionnaires to assess attitudes and values and to obtain environmental and medical information. The proposed battery will be tested on 50 individuals in the Denver area who are representative of the twins' ages. Results of this pilot study will determine the psychometric properties of the battery and the feasibility of administering it to the Swedish and Finnish twins, and any necessary revisions will be made. Subsequent proposals will be written for administrations of the battery to samples of separated and unseparated twins in proposed cross-sectional and longitudinal studies of behavioral aging.